# MCNPX dose result is too small

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1. Mar 2, 2015

### Kim Jae ryang

I want to calculate absorbed dose by MCNP and phantom.
describe x-ray tube and set radiation filed is 30cm x 30cm
I use SRS-78, describe sorce card. 100kev 20mAs 14degree target is tungsten and film is Al 3mm.

I use *f6 tally
so I convert jerk/g ->Mev/g use 1Mev = 1.60E-22jerk
and then Mev/g->Gy use 1gy=6.24E+07mev/g
finallt comply photon number, electron's number (0.02A/1.602*10-19c) * electron->phton convert percentage (0.002072)

then ESD is 1.08E-30 -> 0.027882mGy
and real esd is 2.41mGy... my result is too small... ;(

Code (Text):

cell card
666 0   11 -12 13 -14 16 -17  fill=1000  imp:p,e=1 $phantom box *trcl=(0 0 0 180 90 90 90 0 90 90 90 180 999 0 99 imp:p,e=0$ exterior - zero importance
101 101 -11.34 -110 120 310              imp:p,e=1                               $out 201 201 -1e-20 -120 #310 imp:p,e=1$ in
310 201 -1e-20 -310                      imp:p,e=1                               $hole 401 401 -1.19 -401 imp:p,e=1$ table
255 301 -4.0866e-05 -255 imp:p,e=1
888 301 -4.0866e-05  -99 #101 #310 #201 401 255 #666  imp:p,e=1                            $remainder C ****************************************************************************** C Surface cards C ****************************************************************************** 7 rpp 0 0.40702 0 0.40702 0 0.41494 11 px -26.4563$ phantom box
12  px  26.4563
13  py -10.98954
14  py  10.98954
16  pz -85.47764
17  pz  85.47764
99  so  200  $exterior boundary 401 rpp -30 30 10.99 15.99 -90 120$ table
c 310 arb -0.75 -95 26.5   -0.75 -95 23.5    0.75 -95 26.5    0.75 -95 23.5 &
c          -1.05 -93 26.8   -1.05 -93 23.2   1.05 -93 26.8   1.05 -93 23.2 &
c          1234 5678 1256 2367 3478 1458
310 arb -1.05 -93 26.8  -1.05 -93 23.2  1.05 -93 26.8  1.05 -93 23.2
0 -100 25 0 0 0 0 0 0 0 0 0 1234 1250 1350 2450 3450 0
110 rpp -10 10 -105 -93  0 60                                                   $out 120 rpp -7 7 -103 -95 3 57$ in
255 rpp -10 10  -11.15 -10.99 5 45                                             $dosimeter C ****************************************************************************** C Data cards C ****************************************************************************** mode p c ***************************external source definition ************************ sdef erg=d1 par=p vec=0 1 0 x=d2 y=-100 z=d3 # si1 sp1$ 100kev/photon per
H       D
0.0055  0
0.0060 2.53787E-36
0.0065 4.53838E-28
0.0070 7.90870E-22
0.0075 4.60489E-17
0.0080 2.27444E-13
0.0085 2.32820E-09
0.0090 3.80753E-08
0.0095 2.48905E-05
0.0100 6.76525E-04
0.0105 6.50982E-04
0.0110 7.32045E-03
0.0115 1.29870E-01
0.0120 2.14734E-01
0.0125 7.89059E-01
0.0130 2.81979E+00
0.0135 8.54959E+00
0.0140 2.12839E+01
0.0145 4.84736E+01
0.0150 9.98039E+01
0.0155 1.89155E+02
0.0160 3.34992E+02
0.0165 5.51036E+02
0.0170 8.70073E+02
0.0175 1.29511E+03
0.0180 1.86130E+03
0.0185 2.58252E+03
0.0190 3.45899E+03
0.0195 4.51790E+03
0.0200 5.74212E+03
0.0205 7.10781E+03
0.0210 8.70630E+03
0.0215 1.03834E+04
0.0220 1.22547E+04
0.0225 1.41938E+04
0.0230 1.62758E+04
0.0235 1.83238E+04
0.0240 2.05871E+04
0.0245 2.27133E+04
0.0250 2.48106E+04
0.0255 2.70535E+04
0.0260 2.92121E+04
0.0265 3.12390E+04
0.0270 3.33473E+04
0.0275 3.52724E+04
0.0280 3.72598E+04
0.0285 3.89947E+04
0.0290 4.07637E+04
0.0295 4.22247E+04
0.0300 4.36956E+04
0.0305 4.51762E+04
0.0310 4.62913E+04
0.0315 4.75532E+04
0.0320 4.85658E+04
0.0325 4.95373E+04
0.0330 5.03755E+04
0.0335 5.11067E+04
0.0340 5.17434E+04
0.0345 5.23314E+04
0.0350 5.27595E+04
0.0355 5.31692E+04
0.0360 5.34815E+04
0.0365 5.36802E+04
0.0370 5.38625E+04
0.0375 5.39485E+04
0.0380 5.40203E+04
0.0385 5.39978E+04
0.0390 5.39147E+04
0.0395 5.38207E+04
0.0400 5.36686E+04
0.0405 5.34596E+04
0.0410 5.32113E+04
0.0415 5.29090E+04
0.0420 5.26018E+04
0.0425 5.22902E+04
0.0430 5.18971E+04
0.0435 5.15484E+04
0.0440 5.11055E+04
0.0445 5.06928E+04
0.0450 5.02196E+04
0.0455 4.97774E+04
0.0460 4.92918E+04
0.0465 4.87643E+04
0.0470 4.82981E+04
0.0475 4.77767E+04
0.0480 4.72306E+04
0.0485 4.67309E+04
0.0490 4.61933E+04
0.0495 4.56191E+04
0.0500 4.50884E+04
0.0505 4.45276E+04
0.0510 4.39724E+04
0.0515 4.34214E+04
0.0520 4.28426E+04
0.0525 4.23043E+04
0.0530 4.17376E+04
0.0535 4.11770E+04
0.0540 4.06226E+04
0.0545 4.00416E+04
0.0550 3.94994E+04
0.0555 3.89313E+04
0.0560 3.83698E+04
0.0565 3.78146E+04
0.0570 3.72656E+04
0.0575 3.67225E+04
0.0580 1.23163E+05
0.0585 3.56251E+04
0.0590 3.50996E+04
0.0595 1.88026E+05
0.0600 3.40095E+04
0.0605 3.34735E+04
0.0610 3.29431E+04
0.0615 3.24184E+04
0.0620 3.18991E+04
0.0625 3.13850E+04
0.0630 3.08510E+04
0.0635 3.03473E+04
0.0640 2.98484E+04
0.0645 2.93304E+04
0.0650 2.88176E+04
0.0655 2.83319E+04
0.0660 2.78289E+04
0.0665 2.73305E+04
0.0670 7.95528E+04
0.0675 2.63477E+04
0.0680 2.58629E+04
0.0685 2.53824E+04
0.0690 3.88928E+04
0.0695 2.39214E+04
0.0700 2.09638E+04
0.0705 2.06428E+04
0.0710 2.03035E+04
0.0715 1.99791E+04
0.0720 1.96530E+04
0.0725 1.93095E+04
0.0730 1.89802E+04
0.0735 1.86343E+04
0.0740 1.83022E+04
0.0745 1.79541E+04
0.0750 1.76193E+04
0.0755 1.72691E+04
0.0760 1.69182E+04
0.0765 1.65799E+04
0.0770 1.62271E+04
0.0775 1.58738E+04
0.0780 1.55325E+04
0.0785 1.51777E+04
0.0790 1.48223E+04
0.0795 1.44665E+04
0.0800 1.41103E+04
0.0805 1.37538E+04
0.0810 1.33969E+04
0.0815 1.30397E+04
0.0820 1.26925E+04
0.0825 1.23345E+04
0.0830 1.19764E+04
0.0835 1.16182E+04
0.0840 1.12507E+04
0.0845 1.08927E+04
0.0850 1.05345E+04
0.0855 1.01766E+04
0.0860 9.81862E+03
0.0865 9.46077E+03
0.0870 9.10319E+03
0.0875 8.74571E+03
0.0880 8.38856E+03
0.0885 8.02516E+03
0.0890 7.66889E+03
0.0895 7.31300E+03
0.0900 6.95752E+03
0.0905 6.59716E+03
0.0910 6.24292E+03
0.0915 5.88924E+03
0.0920 5.53613E+03
0.0925 5.17944E+03
0.0930 4.82790E+03
0.0935 4.47707E+03
0.0940 4.12365E+03
0.0945 3.77464E+03
0.0950 3.42647E+03
0.0955 3.07668E+03
0.0960 2.73057E+03
0.0965 2.38544E+03
0.0970 2.03966E+03
0.0975 1.69685E+03
0.0980 1.35403E+03
0.0985 1.01373E+03
0.0990 6.74065E+02
0.0995 3.36438E+02
0.1000 2.80147E+01
si2 h -2.5 2.5
sp2 0 1
si3 h 22.5 27.5
sp3 0 1
c ******************************************************************************
c
c ***************************internal source definition ************************
c ******************************************************************************
nps 10e7
c ------------------------------------------------------------------------------
*f106:p (10<555)  $rbm *f126:p (12<555)$ colon
*f146:p (14<555)  $lung *f166:p (16<555)$ stomach
*f186:p ((18 19)<555)  $breast (adipose tissue) *f206:p (20<555)$ ovary
*f226:p (22<555)  $bladder *f246:p (24<555)$ oesphagus
*f266:p (26<555)  $liver *f286:p (28<555)$ thyroid
*f306:p (30<555)  $bone *f326:p (32<555)$ brain
*f346:p (34<555)  $salivary glands *f366:p (36<555)$ skin
*f386:p (38<555)  $Adrenals *f406:p (40<555)$ ET region
*f426:p (42<555)  $Gall bladder *f446:p (44<555)$ Heart
*f466:p (46<555)  $Kidneys *f486:p (48<555)$ Blood (Lymphatic nodes)
*f506:p (50<555)  $Muscle *f526:p (52<555)$ Oral mucosa
*f546:p (54<555)  $Pancreas *f566:p (56<555)$ Uterus
*f586:p (58<555)  $Small intestine *f606:p (60<555)$ Spleen
*f626:p (62<555)  $Thymus *f646:p (64<555)$ Eyes
*f666:p (66<555)  $Lens *f686:p (68<555)$ Spinal cords
*f706:p (70<555)  $Teeth *f726:p (72<555)$ Tongue
*f746:p (74<555)  $Tonsils *f766:p (76<555)$ Trachea
*f786:p (78<555)  $Bronchi *f806:p (80<555)$ Ureter
*f826:p (82<555)  $Pallopian tubes *f846:p (84<555)$ Vagina
*f906:p (90<555)  $Residual tissue *f996:p 401 *f986:p255 ------------------------------------------------------------------------------- read file=HDRK-Woman_mat noecho m101 82000 1.0$lead
m401  6000  1.0                                                                  $C m201 8000 0.2 7000 0.8$vacuum
m301   6000 -0.000124                                                            $C 7014 -0.755636$N
8016 -0.231475                                                            $O 18000 -0.012889$Ar

Last edited by a moderator: Mar 4, 2015
2. Mar 7, 2015